diff --git a/custom_components/spook/ectoplasms/homeassistant/templating/is_on.py b/custom_components/spook/ectoplasms/homeassistant/templating/is_on.py
new file mode 100644
index 00000000..a29fcc3b
--- /dev/null
+++ b/custom_components/spook/ectoplasms/homeassistant/templating/is_on.py
@@ -0,0 +1,38 @@
+"""Spook - Not your homie."""
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, Any
+
+from homeassistant.helpers.template import is_state
+
+from ....templating import AbstractSpookTemplateFunction
+
+if TYPE_CHECKING:
+    from collections.abc import Callable
+
+
+class SpookTemplateFunction(AbstractSpookTemplateFunction):
+    """Spook template function to test if an entity is "on"."""
+
+    name = "is_on"
+    test_name = "on"
+
+    is_filter = True
+    is_global = True
+    is_test = True
+
+    def _function(
+        self,
+        entity_id: str | list[str],
+    ) -> bool:
+        """Check if the current state of an entity is."""
+        if isinstance(entity_id, list):
+            return all(
+                entity_id == "on" or is_state(self.hass, entity, "on")
+                for entity in entity_id
+            )
+        return entity_id == "on" or is_state(self.hass, entity_id, "on")
+
+    def function(self) -> Callable[..., Any]:
+        """Return the python method that runs this template function."""
+        return self._function